The Society of Automotive Engineers (hereinafter “SAE”) publishes many new, revised and reaffirmed standards each year in three categories, including Ground Vehicle Standards, which are also referred to as the J-Standards. Information on these standards is available on the World Wide Web at the SAE website.
The SAE standards specify certain photometric requirements for vehicle lamps including candela requirements and locations from which the requirements are measured. SAE standard J2039 (May 2001) is the current standard for side turn signal lamps for long vehicles. SAE standard J592 (August 2000) is the current SAE standard for clearance, side marker, and identification lamps. The Department of Transportation (DOT), however, in its Federal Motor Vehicle Safety Standards, 49 C.F.R. §571.108 (2000), (“FMVSS 108”) has adopted SAE Standard J592e (1972) for clearance, side marker, and identification lamps.
J2039 standard defines a side turn lamp as the signaling element of a turn signal system, which indicates a change in vehicle direction by giving a flashing light on the side toward which the turn or lane change will be made. J2039 provides test procedures, requirements and guidelines for side turn signal lamps intended for use in trailers 12 meters or more in overall length. The side turn signals may also be used on other large vehicles such as trucks, truck tractors, buses and any other application where this type of lighting is desired.
A turn, or directional, signal lamp should be visible, if possible, from any point with respect to the vehicle. Moreover, to be considered visible, the lamp should provide a minimum of 13 cm2 of unobstructed projected area when the light emitting surface of the lens is projected parallel to a horizontal plane in any direction from 0 degrees to 85 degrees right for curbside lamp and to a vertical place in any direction from 35 degrees above to 20 degrees below the horizontal with respect to the lamp H-V axis. This is difficult to accomplish in a large vehicle. Therefore, a separate turn signal is usually mounted on both the road side of the truck and the curb side of the truck. The term road side is used to refer to the driver side of the vehicle and the term curb side is used to mean the passenger side of the vehicle. Specifically, the side turn lamp is mounted behind the front wheel on the road side and the curb side of the vehicle to supplement the forward turn signal lamp.
SAE J592 (August 2000) and SAE Standard J592e (1972), which relate to sidemarker lamps, defines a sidemarker lamp as a lighting device used to indicate the presence of and length of the vehicle when viewed from the side. J592 provides test procedures, requirements and guidelines for sidemarker lamps intended for use on road vehicles less than 2032 mm in overall width.
Reprinted hereinbelow are the photometric performance requirements for side turn lamps, as recited in Table 1 of J2039, and the photometric performance requirements for sidemarker lamps, as recited in Table 1 of J592e. The entirety of SAE Standard J2039 (May 2001), SAE Standard J592 (August 2000), SAE Standard J592e (1972), and DOT Standard 592e (part of FMVSS 108) are incorporated herein by reference.
TABLE 1SIDE TURN SIGNAL LAMP PHOTOMETRIC PERFORMANCE REQUIREMENTS(1)Curbside Lamps(2)Minimum(Right Hand)LuminousZone TotalTest PointIntensityLuminous Intensity,ZoneDegreesCandela(3)Candela(4)135U-45R1296   -30R1220U-60R2010D-60R2015D-45R1620D-30R16235U-V1298H-30R40H-V3020D-V16320U-75R20120H-45R50H-85R305D-75R20Maximum Luminous200Intensity, Candela(5)(within the photometric pattern)Maximum Luminous85L-90L50Intensity, Candela(5(6))H and above(1)Ratio Requirements of 6.1.5..2 apply.(2)This table shows the zone totals for the curbside lamp requirements. The roadside lamp zone total requirements are symmetrically opposite.(3)The measured values at each individual test point shall not be less than 60% of the required minimum value shown for that individual test point location.(4)The sum of the luminous intensity measurements at each test point within a zone shall not be less than the Zone Total Luminous Intensity shown.(5)The listed maximum shall not be exceeded over any area larger than that generated by a 0.5 degree radius within the solid angle defined by the test points.(6)The forward maximum intensity applies throughout the zone of 85 degrees left to 90 degrees left and horizontal and above.
TABLE 2CLEARANCE, SIDE MARKER, AND IDENTIFICATION LAMPS-PHOTOMETRICREQUIREMENTS SAE J592e(1)MinimumMinimumMinimumZone TotalLuminousLuminousLuminousLuminousTest PointsIntensity (cd)(2)Intensity (cd)(2)Intensity (cd)(3)Intensity (cd)(3)Zone(degrees)RedYellowRedYellowI10U0.250.620.751.86H45L0.250.6210D0.250.62II10U0.250.620.751.86HV0.250.6210D0.250.62III10U0.250.620.751.86H45R0.250.6210D0.250.62Maximum Luminous Intensity (cd)(1)Reduced inboard angle requirement of 6. 1. 5. 2. Apply.(2)The measured values at each individual test point shall not be less then 60% of the required minimum value shown for that individual test point location.(3)The sum of the luminous intensity measurements at each test point within a zone shall not be less than the Zone Total Luminous Intensity shown.